How to grow Trillium
Also known as wake robin or wood lily, trillium is a rhizomatous spring-flowering perennial found growing on moist, woodland floors throughout North America. It has a distinctive cup-and-saucer-like appearance, with a three petalled flower (which can be white, yellow, or dark red) sitting on top of three leaves.
Trilliums are notoriously slow to establish – don’t expect to see flowers in the first season and allow a good few years for a clump to bulk up into anything resembling significant ground cover. Aside from patience and the right growing conditions, however, trilliums ask little of the gardener, making a fuss-free, long-lived addition to the garden. Once established, they promise reliable spring beauty for up to 25 years.
It is important to note that the roots and berries of trillium are toxic to humans, dogs, and cats, and can cause discomfort if ingested. The leaves however are edible (said to have a nutty flavour) and have been traditionally used for medicinal purposes.
Zantedeschia is a genus of flowering plants from the family Araceae and is native to southern Africa. With a rich history dating back to the Ancient Romans, these deciduous or semi-evergreen perennials have been used as a symbol of celebration. Zantedeschia was Named after Professor Giovanni Zantedeschia, an Italian botanist.
There are two main forms of Zantedeschia: hardy and tender. Hardy forms of the plant can be grown outdoors, enjoy moist soil and full sun or partially shaded conditions - these are known as Arum lilies. Tender forms of Zantedeschia prefer being grown in containers or pots and should be brought inside over the winter - these are known as Calla lilies.
With tuberous flora in all colours from whites, yellows and oranges to deep reds and purples, Zantedeschias are not to be overlooked in any garden, as long as they have sufficient sunlight to grow in.
Ready to learn more about growing Zantedeschia? Read on for all there is to know...
Key Information
Soil pH
Position
Hardiness
Where & when to plant Trillium
Position - Deep or partial shade with shelter from strong winds.
Soil - Moist, well-draining, deep, humus-rich soil, preferably with an acid to neutral pH. Alkaline soil will be tolerated as long as it meets the other criteria.
Avoid anywhere prone to drying out or becoming waterlogged.
Flowering Period - Spring
Hardiness - Hardy, usually rated H5 (-10 to -15°C).
Trillium can be bought in two forms: as a bare root rhizome or potted young plant.
Bare root trilliums are best planted in late summer, allowing time for a good root system to be established before the following growing season. Potted young plants on the other hand are best planted whilst in growth, in mid spring.
When it comes to choosing a spot, aim for something as close to a woodland floor as possible (i.e., rich, moist, and shady). Underneath deciduous trees and shrubs is a good bet, or any moist, shady border. These slow-to-establish plants do best without competition, so try to keep the surrounding soil clear of weeds and other plants.
Trilliums rarely thrive in a container, preferring rich, deep garden soil. If you wish to give it a try anyway, go for a sandy loam mix and a nice, deep pot.
How to plant Trillium
· For planting in the ground, first clear the chosen area of weeds.
· Dig a planting hole several times larger than the root ball (if pre-potted), or bare root rhizome. It is a good idea to mix in some well-rotted organic matter at this stage. Leaf mould is ideal, though garden compost or manure also work well.
· Place in the hole, with the rhizome at a depth of 7 to 10 centimetres.
· Backfill with soil and firm in gently.
· Soak well with water.
· For planting in a container, choose a deep, large pot with plenty of drainage holes in the bottom.
· It can be a good idea to fill and plant this in situ to save yourself the trouble of moving once full.
· Use a good quality loam based potting compost with added sharp sand and leaf mould, and, if not already present in the compost (check the description on the bag) some slow-release fertiliser granules.
· Start by partially filling the container with compost; enough so that when placed on the surface the rhizomes are about 10 centimetres lower than the top of the pot.
· Allow approximately 25 centimetres between each rhizome if planting more than one per pot.
· Fill the remainder of the container with compost, firming down with your fingers so the rhizomes are held tight. Make sure there is a small gap between the surface of the compost and the top of the container.
· Pick up the container and lightly tap on the potting bench or ground a few times to help further settle the compost around the plant.
· Soak well with water.
· A mulch with horticultural grit will look attractive and help to prevent a ‘cap’ or crust forming on the top of the compost (something container plants can suffer due to the artificial nature of their watering).
What to plant with Trillium
Though spectacular, the blooming period of trillium is relatively fleeting (a dazzling three weeks or so), so it pays to grow other flowering woodlanders nearby. Tiarella, erythronium, corydalis, and violets all enjoy similar growing conditions and fit the bill perfectly. Just remember trillium prefers plenty of elbow room, so don’t plant anything too close to it.
How to care for Trillium
Pruning and Deadheading
Trillium requires very little attention and will die back naturally each year. It is usually completely gone by mid-autumn.
Watering
Trillium enjoys moist conditions, starting with a good soak on planting. After this, water during any hot, dry spells in the growing season, though take care not to overdo it as waterlogged soil can be as harmful as drought conditions for this plant. A good rule of thumb is to water only once the top few centimetres of soil have dried out.
An annual mulch can be extremely effective in keeping soil moist. More on this next.
Container grown trillium will require you to be more attentive, keeping the compost consistently moist but not soggy. A saucer placed underneath the pot can be helpful.
Feeding
On healthy, fertile soil, an annual mulch of well-rotted organic matter (ideally leaf mould) in early spring should provide sufficient nutrients for your trillium. This has the added benefit of suppressing weeds and locking in moisture.
For an extra boost, apply a light dose of general-purpose granular feed such as blood, fish, and bone to the surface of the soil and lightly work it in. This is known as a ‘top dress’ and is best done in late winter.
Container-grown plants rely more on the gardener for nutrition. Get off to a flying start by making sure you use a good quality compost, then throughout the growing season (March to October) apply a liquid feed every 3-4 weeks.
Cold Protection
Temperature-wise, trillium is hardy enough to withstand a UK winter without the need for additional protection. Its biggest threat is waterlogged soil, so take care to choose a spot where conditions are well-draining all year round.
Pests and Diseases
Mice, rats, and squirrels have a fondness for digging up freshy planted trillium rhizomes, something often not apparent until they fail to grow in early spring. It can be worth protecting with a cloche or covering of chicken wire for those first few months, particularly if you have had trouble with rodents in the past.
You may also find the soft, young leaves susceptible to slug and snail damage. Encouraging natural predators into your garden, such as birds, frogs, toads, and hedgehogs makes a big difference. Torchlight searches after dark (when slugs and snails are at their most active) are also effective, allowing you to collect the offending molluscs in a bucket and dispose of as you see fit. Relocating to a nearby woods or bagging up and putting in your freezer before popping them in the bin are said to be the most humane approaches.
How to propagate Trillium
The easiest way to propagate trillium is by lifting and dividing established clumps as the foliage dies back. It’s worth noting that trillium prefers as little disturbance as possible, so try to keep this practice to a minimum (rather than something you routinely carry out every few years, as is the case with many other perennials).
1. Dig the plant out of the ground.
2. Shake off any excess soil.
3. Separate into separate clumps, ensuring each piece has at least one bud and some roots.
4. Plant as above.
* Many plants carry Plant Breeders Rights and cannot be propagated for commercial purposes.
Common Trillium Questions
· Can you grow trillium from seed?
You can, although this is an exercise in extreme patience as it can take six or seven years for seed-grown plants to reach flowering maturity. Always sow seeds fresh as they don’t store well.
· I’m desperate to grow trillium but my heavy, clay soil isn’t right for them. What can I do?
Try a raised bed filled with a mix of loam, garden compost, well-rotted manure, composted bark, and sharp sand. This will need to be at least 10 centimetres deep to avoid the rhizomes sitting in waterlogged conditions over winter.
